Modeling Of Grid-connected Wind Farm And Study On Its Protection Based On RTDS

Because of its environmentally friendly and high conversion efficiency features, wind power as one of the new forms of energy has been developed tremendously in the world. However, with the scale of the wind farms expanding, uncontrollable and randomness of the wind power also strengthen its influence to the electric grid. And most of the wind farms connected to the power grid located in remote areas, the expansion of installed capacity which is constrainted by the voltage level has also brought a series of questions. With the increasing installed capacity of wind farm, its equipment will become increasingly complex for adapting to the grid requirements. The outstanding problem is the proper selection and configuration of the relay protection equipment to ensure the safe operation. In this paper, the kinds of wind farms which connected to the power grid through the distribution network and the other one which connected to the power gird as large-scale centralized forms will be treated differently. In the traditional wind farm, the impact on the sensitive of relay protection of the system is analysed by it’s short-circuit current, which is similar to imapction on other feeders protection caused by the output power of feeders which is connected to the large-scale centralized wind farms. That’s why this article makes a research on a large-scale centralized access grid wind farm protection issues.Firstly, this paper introduces the structure of the mainstream models of the wind farm, asynchronous induction wind generator, double-fed asynchronous induction wind generator(DFIG) and direct-driven permanent magnet synchronous wind generator (PMSG), make a study on the control strategy through the analysis of their works. Then built the model of the logic control system for wind turbine structures on real-time digital simulator instrument (RTDS), and verify the correctness of the wind turbine control strategy and simulation model of the group through dynamic simulation.In order to study the protection of existing wind farms, wind farm protection configuration, including the protection of the wind turbine configuration, each line of the wind farm protection configuration as well as incorporated into the system step-up substation protection configuration are introduced in this paper. It focuses on the protection of the line, that line belongs to the medium voltage system, the protection configuration is relatively simple. By analyzing the impaction on the power system protection by the wind farm, point out the problems of the large-scale wind farm protection, and verify the problems through modeling and simulation of the actual wind farm, pointing out that due to the instability, randomness of wind power and the difference between the line in the conventional system and the line in the wind farm caused the accident protection malfunction or tripping.Through analysis, the protection configuration improvement program of the line inside the wind farm is put forward.in which the adaptive current protection is proposed for wind farm feeder line phase fault current protection instead of three sect current protections, analyze the principle of adaptive current protection with wind power and the formula parameter tuning method of calculation in detail. To quickly remove the fault propose the two ways which are grounding resistance or arc suppression coil for single-phase ground fault, through the selection of the grounding resistance or arc suppression coil as well as the grounding transformers for the ungrounding system for the wind farm, and studied the application of different wiring the wind farm, then gives the actual wind farm single-phase ground fault protection setting value. However, further studies are needed for more accurate wind farm equipment protection.